Metabolic
Creatine Kinase
LOINC 2157-6 · U/L
What it is
Creatine kinase (CK) is an enzyme found mainly in muscle. It is released into the blood when muscle is stressed or damaged.
Why it matters
CK is used to detect muscle injury, including from intense exercise, and occasionally heart or muscle disease.
What high values can mean
A higher value commonly follows strenuous exercise or muscle injury, and can relate to some medications or muscle conditions.
What low values can mean
A lower value is usually not clinically significant.
How to improve it
A short-lived rise after exercise settles with rest; persistent elevation needs its cause investigated.
Food & lifestyle
Staying hydrated and allowing recovery after heavy exercise helps keep CK in a normal range.
Preparing for the test
A blood test; avoid intense exercise for a day or two beforehand, as it can raise CK — follow your lab.
When to talk to a doctor
Discuss a persistently high CK with a doctor, especially with muscle pain, weakness or dark urine.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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